Charpentier'fl Essay on Glaciers, 1|# 



that a belief in the transportation of erratic blocks by gUciers, 

 greatly superior in size and extent to those now existing, i$ 

 shared by many of the simple mountaineers of the Alps, who, 

 whether from vague tradition, or, what is more probable, the 

 habit of observation which is peculiar to them, have anticipated 

 geologists by admitting this theory as a fact. It likewise ap- 

 pears that M. Esmark of Christiania had admitted,* in 1827, 

 that the blocks of granite dispersed in such great numbers 

 through Norway, had been conveyed by ancient glaciers. 



But, confining for the present the application of the theory 

 to the Alps, it must be admitted that, after the last elevation of 

 this chain of mountains, thewarm climate (about 17°.5(63°.5F.) 

 which had, till then, prevailed in their vicinity, and which was 

 sufficient to allow palms to flourish, since remains of them are 

 found in the deposits formed at their base, gave place to a cold 

 and humid climate ; that, during this epoch, glaciers were 

 formed on the highest summits of the Alps and on the most 

 elevated ridges of the secondary chains ; that these glaciers 

 increased to such an extent that they descended to the lateral 

 valleys, and filled them to a certain height, and finally reached 

 the great principal valley, where they united into one which 

 ended by debouching into the basin of lower Switzerland. Thua 

 all the great valleys of the Alps would furnish an extensive 

 glacier reaching to the plain situate at their foot ; but one 

 only, that of the valley of the Rhone, would acquire such ex- 

 tension as to traverse the plain and reach almost to the high- 

 est points of the Jura. The return of heat would gradually 

 melt these enormous glaciers, and reduce them to their present 

 dimensions, while the debris which they carried with them, as is 

 seen in modern glaciers in our own day, would serve as marks to 

 point out their progress, and constitute the erratic formation. 



Of the hypothesis of great diluvial glaciers thus announced, 

 M. de Charpentier endeavours to demonstrate that it explains 

 all the phenomena observed respecting the distribution of the 

 erratic formation, when we take into account the facts pre- 

 sented by existing glaciers. Thus the erratic matter of each 

 of the great valleys of Switzerland always presents a collec- 

 tion of all tlie rocks entering into the composition of the moun* 



♦ See Esmark's paper on tUe Geological History of tbeEartli. Jame«on'» 

 Journal, vol. ii. p. 113. 



